The Japanese journal of physiology最新文献

{"title":"Impact of vesicular glutamate leakage on synaptic transmission at the calyx of Held","authors":"Chihiro Takami, Kohgaku Eguchi, T. Hori, Tomoyuki Takahashi","doi":"10.1113/JP273467","DOIUrl":"https://doi.org/10.1113/JP273467","url":null,"abstract":"It is controversial whether glutamate can leak out of vesicles in the nerve terminal. To address this issue, we abolished vesicular glutamate uptake by washing out presynaptic cytosolic glutamate or by blocking vacuolar ATPase activity using bafilomycin A1. In the absence of vesicular glutamate uptake, both spontaneous and nerve‐evoked EPSCs underwent a rundown, suggesting that vesicular glutamate can leak out of vesicles. However, the rundown of evoked EPSCs was caused mainly by accumulation of unfilled vesicles after exocytic release of glutamate, suggesting a minor influence of glutamate leakage on synaptic transmission.","PeriodicalId":22512,"journal":{"name":"The Japanese journal of physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88531301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cerebral haemodynamic response to somatosensory stimulation in near‐term fetal sheep","authors":"S. Nakamura, D. Walker, F. Wong","doi":"10.1113/JP273163","DOIUrl":"https://doi.org/10.1113/JP273163","url":null,"abstract":"Cerebral haemodynamic response to neural stimulation has been extensively investigated in animal and clinical studies, in both adult and paediatric populations, but little is known about cerebral haemodynamic functional response in the fetal brain. The present study describes the cerebral haemodynamic response measured by near‐infrared spectroscopy to somatosensory stimulation in fetal sheep. The cerebral haemodynamic response in the fetal sheep brain changes from a positive (increase in oxyhaemoglobin (oxyHb)) response pattern to a negative or biphasic response pattern when the duration of somatosensory stimulation is increased, probably due to cerebral vasoconstriction with prolonged stimulations. In contrast to adult studies, we have found that changes in fetal cerebral blood flow and oxyHb are positively increased in response to somatosensory stimulation during hypercapnia. We propose this is related to reduced vascular resistance and recruitment of cerebral vasculature in the fetal brain during hypercapnia.","PeriodicalId":22512,"journal":{"name":"The Japanese journal of physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89404796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FoxO‐dependent atrogenes vary among catabolic conditions and play a key role in muscle atrophy induced by hindlimb suspension","authors":"L. Brocca, L. Toniolo, C. Reggiani, R. Bottinelli, M. Sandri, M. Pellegrino","doi":"10.1113/JP273097","DOIUrl":"https://doi.org/10.1113/JP273097","url":null,"abstract":"Muscle atrophy is a debilitating condition that affects a high percentage of the population with a negative impact on quality of life. Dissecting the molecular level of the atrophy process, and the similarities/dissimilarities among different catabolic conditions, is a necessary step for designing specific countermeasures to attenuate/prevent muscle loss. The FoxO family transcription factors represent one of the most important regulators of atrophy programme stimulating the expression of many atrophy‐related genes. The findings of the present study clearly indicate that the signalling network controlling the atrophy programme is specific for each catabolic condition.","PeriodicalId":22512,"journal":{"name":"The Japanese journal of physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83313014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cholinergic modulation of the parafacial respiratory group","authors":"Rozlyn C. T. Boutin, Zaki Alsahafi, S. Pagliardini","doi":"10.1113/JP273012","DOIUrl":"https://doi.org/10.1113/JP273012","url":null,"abstract":"This study investigates the effects of cholinergic transmission on the expiratory oscillator, the parafacial respiratory group (pFRG) in urethane anaesthetized adult rats. Local inhibition of the acetyl cholinesterase enzyme induced activation of expiratory abdominal muscles and active expiration. Local application of the cholinomimetic carbachol elicited recruitment of late expiratory neurons, expiratory abdominal muscle activity and active expiration. This effect was antagonized by local application of the muscarinic antagonists scopolamine, J104129 and 4DAMP. We observed distinct physiological responses between the more medial chemosensitive region of the retrotrapezoid nucleus and the more lateral region of pFRG. These results support the hypothesis that pFRG is under cholinergic neuromodulation and the region surrounding the facial nucleus contains a group of neurons with distinct physiological roles.","PeriodicalId":22512,"journal":{"name":"The Japanese journal of physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90727837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non‐uniform phase sensitivity in spatial frequency maps of the human visual cortex","authors":"R. Farivar, S. Clavagnier, Bruce C. Hansen, Ben Thompson, R. Hess","doi":"10.1113/JP273206","DOIUrl":"https://doi.org/10.1113/JP273206","url":null,"abstract":"Just as a portrait painting can come from a collection of coarse and fine details, natural vision can be decomposed into coarse and fine components. Previous studies have shown that the early visual areas in the brain represent these components in a map‐like fashion. Other studies have shown that these same visual areas can be sensitive to how coarse and fine features line up in space. We found that the brain actually jointly represents both the scale of the feature (fine, medium, or coarse) and the alignment of these features in space. The results suggest that the visual cortex has an optimized representation particularly for the alignment of fine details, which are crucial in understanding the visual scene.","PeriodicalId":22512,"journal":{"name":"The Japanese journal of physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91302385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Systematic evaluation of the impact of stimulation intensity on neuroplastic after-effects induced by transcranial direct current stimulation.","authors":"Asif Jamil, Giorgi Batsikadze, Hsiao-I Kuo, Ludovica Labruna, Alkomiet Hasan, Walter Paulus, Michael A Nitsche","doi":"10.1113/JP272738","DOIUrl":"10.1113/JP272738","url":null,"abstract":"<p><strong>Key points: </strong>Applications of transcranial direct current stimulation to modulate human neuroplasticity have increased in research and clinical settings. However, the need for longer-lasting effects, combined with marked inter-individual variability, necessitates a deeper understanding of the relationship between stimulation parameters and physiological effects. We systematically investigated the full DC intensity range (0.5-2.0 mA) for both anodal and cathodal tDCS in a sham-controlled repeated measures design, monitoring changes in motor-cortical excitability via transcranial magnetic stimulation up to 2 h after stimulation. For both tDCS polarities, the excitability after-effects did not linearly correlate with increasing DC intensity; effects of lower intensities (0.5, 1.0 mA) showed equal, if not greater effects in motor-cortical excitability. Further, while intra-individual responses showed good reliability, inter-individual sensitivity to TMS accounted for a modest percentage of the variance in the early after-effects of 1.0 mA anodal tDCS, which may be of practical relevance for future optimizations.</p><p><strong>Abstract: </strong>Contemporary non-invasive neuromodulatory techniques, such as transcranial direct current stimulation (tDCS), have shown promising potential in both restituting impairments in cortical physiology in clinical settings, as well as modulating cognitive abilities in the healthy population. However, neuroplastic after-effects of tDCS are highly dependent on stimulation parameters, relatively short lasting, and not expectedly uniform between individuals. The present study systematically investigates the full range of current intensity between 0.5 and 2.0 mA on left primary motor cortex (M1) plasticity, as well as the impact of individual-level covariates on explaining inter-individual variability. Thirty-eight healthy subjects were divided into groups of anodal and cathodal tDCS. Five DC intensities (sham, 0.5, 1.0, 1.5 and 2.0 mA) were investigated in separate sessions. Using transcranial magnetic stimulation (TMS), 25 motor-evoked potentials (MEPs) were recorded before, and 10 time points up to 2 h following 15 min of tDCS. Repeated-measures ANOVAs indicated a main effect of intensity for both anodal and cathodal tDCS. With anodal tDCS, all active intensities resulted in equivalent facilitatory effects relative to sham while for cathodal tDCS, only 1.0 mA resulted in sustained excitability diminution. An additional experiment conducted to assess intra-individual variability revealed generally good reliability of 1.0 mA anodal tDCS (ICC(2,1) = 0.74 over the first 30 min). A post hoc analysis to discern sources of inter-individual variability confirmed a previous finding in which individual TMS SI_1mV (stimulus intensity for 1 mV MEP amplitude) sensitivity correlated negatively with 1.0 mA anodal tDCS effects on excitability. Our study thus provides further insights on the extent of non-l","PeriodicalId":22512,"journal":{"name":"The Japanese journal of physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5309387/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74025151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tonotopic action potential tuning of maturing auditory neurons through endogenous ATP","authors":"Saša Virijević Jovanović, T. Radulovic, C. Coddou, Beatrice Dietz, Jana Nerlich, S. Stojilkovic, R. Rübsamen, I. Milenkovic","doi":"10.1113/JP273272","DOIUrl":"https://doi.org/10.1113/JP273272","url":null,"abstract":"Following the genetically controlled formation of neuronal circuits, early firing activity guides the development of sensory maps in the auditory, visual and somatosensory system. However, it is not clear whether the activity of central auditory neurons is specifically regulated depending on the position within the sensory map. In the ventral cochlear nucleus, the first central station along the auditory pathway, we describe a mechanism through which paracrine ATP signalling enhances firing in a cell‐specific and tonotopically‐determined manner. Developmental down‐regulation of P2X2/3R currents along the tonotopic axis occurs simultaneously with an increase in AMPA receptor currents, suggesting a high‐to‐low frequency maturation pattern. Facilitated action potential (AP) generation, measured as higher firing rate, shorter EPSP‐AP delay in vivo and shorter AP latency in slice experiments, is consistent with increased synaptic efficacy caused by ATP. The long lasting change in intrinsic neuronal excitability is mediated by the heteromeric P2X2/3 receptors.","PeriodicalId":22512,"journal":{"name":"The Japanese journal of physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80629478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Minimum number of myosin motors accounting for shortening velocity under zero load in skeletal muscle","authors":"L. Fusi, Valentina Percario, E. Brunello, M. Caremani, P. Bianco, J. Powers, M. Reconditi, V. Lombardi, G. Piazzesi","doi":"10.1113/JP273299","DOIUrl":"https://doi.org/10.1113/JP273299","url":null,"abstract":"Myosin filament mechanosensing determines the efficiency of the contraction by adapting the number of switched ON motors to the load. Accordingly, the unloaded shortening velocity (V0) is already set at the end of latency relaxation (LR), ∼10 ms after the start of stimulation, when the myosin filament is still in the OFF state. Here the number of actin‐attached motors per half‐myosin filament (n) during V0 shortening imposed either at the end of LR or at the plateau of the isometric contraction is estimated from the relation between half‐sarcomere compliance and force during the force redevelopment after shortening. The value of n decreases progressively with shortening and, during V0 shortening starting at the end of LR, is 1–4. Reduction of n is accounted for by a constant duty ratio of 0.05 and a parallel switching OFF of motors, explaining the very low rate of ATP utilization found during unloaded shortening.","PeriodicalId":22512,"journal":{"name":"The Japanese journal of physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86638451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence of viscerally‐mediated cold‐defence thermoeffector responses in man","authors":"N. Morris, D. Filingeri, M. Halaki, O. Jay","doi":"10.1113/JP273052","DOIUrl":"https://doi.org/10.1113/JP273052","url":null,"abstract":"Visceral thermoreceptors that modify thermoregulatory responses are widely accepted in animal but not human thermoregulation models. Recently, we have provided evidence of viscerally‐mediated sweating alterations in humans during exercise brought about by warm and cool fluid ingestion. In the present study, we characterize the modification of shivering and whole‐body thermal sensation during cold stress following the administration of a graded thermal stimuli delivered to the stomach via fluid ingestion at 52, 37, 22 and 7°C. Despite no differences in core and skin temperature, fluid ingestion at 52°C rapidly decreased shivering and sensations of cold compared to 37°C, whereas fluid ingestion at 22 and 7°C led to equivalent increases in these responses. Warm and cold fluid ingestion independently modifies cold defence thermoeffector responses, supporting the presence of visceral thermoreceptors in humans. However, the cold‐defence thermoeffector response patterns differed from previously identified hot‐defence thermoeffectors.","PeriodicalId":22512,"journal":{"name":"The Japanese journal of physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75239705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Excitation of lateral habenula neurons as a neural mechanism underlying ethanol‐induced conditioned taste aversion","authors":"Shashank Tandon, K. Keefe, S. Taha","doi":"10.1113/JP272994","DOIUrl":"https://doi.org/10.1113/JP272994","url":null,"abstract":"The lateral habenula (LHb) has been implicated in regulation of drug‐seeking behaviours through aversion‐mediated learning. In this study, we recorded neuronal activity in the LHb of rats during an operant task before and after ethanol‐induced conditioned taste aversion (CTA) to saccharin. Ethanol‐induced CTA caused significantly higher baseline firing rates in LHb neurons, as well as elevated firing rates in response to cue presentation, lever press and saccharin taste. In a separate cohort of rats, we found that bilateral LHb lesions blocked ethanol‐induced CTA. Our results strongly suggest that excitation of LHb neurons is required for ethanol‐induced CTA, and point towards a mechanism through which LHb firing may regulate voluntary ethanol consumption.","PeriodicalId":22512,"journal":{"name":"The Japanese journal of physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87261114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}